Filters Aggregation Usageedit

Defines a multi bucket aggregations where each bucket is associated with a filter. Each bucket will collect all documents that match its associated filter. For documents that do not match any filter, these will be collected in the other bucket.

Be sure to read the Elasticsearch documentation Filters Aggregation

Named filtersedit

Fluent DSL exampleedit

s => s
.Aggregations(aggs => aggs
    .Filters("projects_by_state", agg => agg
        .OtherBucket()
        .OtherBucketKey("other_states_of_being")
        .NamedFilters(filters => filters
            .Filter("belly_up", f => f.Term(p => p.State, StateOfBeing.BellyUp))
            .Filter("stable", f => f.Term(p => p.State, StateOfBeing.Stable))
            .Filter("very_active", f => f.Term(p => p.State, StateOfBeing.VeryActive))
        )
        .Aggregations(childAggs => childAggs
            .Terms("project_tags", avg => avg.Field(p => p.CuratedTags.First().Name.Suffix("keyword")))
        )
    )
)

Object Initializer syntax exampleedit

new SearchRequest<Project>
{
    Aggregations = new FiltersAggregation("projects_by_state")
    {
        OtherBucket = true,
        OtherBucketKey = "other_states_of_being",
        Filters = new NamedFiltersContainer
        {
                { "belly_up", Query<Project>.Term(p=>p.State, StateOfBeing.BellyUp) },
                { "stable", Query<Project>.Term(p=>p.State, StateOfBeing.Stable) },
                { "very_active", Query<Project>.Term(p=>p.State, StateOfBeing.VeryActive) }
        },
        Aggregations =
            new TermsAggregation("project_tags") { Field = Field<Project>(p => p.CuratedTags.First().Name.Suffix("keyword")) }
    }
}

Example json output. 

{
  "aggs": {
    "projects_by_state": {
      "filters": {
        "other_bucket": true,
        "other_bucket_key": "other_states_of_being",
        "filters": {
          "belly_up": {
            "term": {
              "state": {
                "value": "BellyUp"
              }
            }
          },
          "stable": {
            "term": {
              "state": {
                "value": "Stable"
              }
            }
          },
          "very_active": {
            "term": {
              "state": {
                "value": "VeryActive"
              }
            }
          }
        }
      },
      "aggs": {
        "project_tags": {
          "terms": {
            "field": "curatedTags.name.keyword"
          }
        }
      }
    }
  }
}

Handling Responsesedit

Using the .Agg aggregation helper we can fetch our aggregation results easily in the correct type. Be sure to read more about .Aggs vs .Aggregations

response.ShouldBeValid();

var filterAgg = response.Aggs.Filters("projects_by_state");
filterAgg.Should().NotBeNull();

var namedResult = filterAgg.NamedBucket("belly_up");
namedResult.Should().NotBeNull();
namedResult.DocCount.Should().BeGreaterThan(0);

namedResult = filterAgg.NamedBucket("stable");
namedResult.Should().NotBeNull();
namedResult.DocCount.Should().BeGreaterThan(0);

namedResult = filterAgg.NamedBucket("very_active");
namedResult.Should().NotBeNull();
namedResult.DocCount.Should().BeGreaterThan(0);

namedResult = filterAgg.NamedBucket("other_states_of_being");
namedResult.Should().NotBeNull();
namedResult.DocCount.Should().Be(0);

Anonymous filtersedit

Fluent DSL exampleedit

s => s
.Aggregations(aggs => aggs
    .Filters("projects_by_state", agg => agg
        .OtherBucket()
        .AnonymousFilters(
            f => f.Term(p => p.State, StateOfBeing.BellyUp),
            f => f.Term(p => p.State, StateOfBeing.Stable),
            f => f.Term(p => p.State, StateOfBeing.VeryActive)
        )
        .Aggregations(childAggs => childAggs
            .Terms("project_tags", avg => avg.Field(p => p.CuratedTags.First().Name.Suffix("keyword")))
        )
    )
)

Object Initializer syntax exampleedit

new SearchRequest<Project>
{
    Aggregations = new FiltersAggregation("projects_by_state")
    {
        OtherBucket = true,
        Filters = new List<QueryContainer>
        {
                 Query<Project>.Term(p=>p.State, StateOfBeing.BellyUp) ,
                 Query<Project>.Term(p=>p.State, StateOfBeing.Stable) ,
                 Query<Project>.Term(p=>p.State, StateOfBeing.VeryActive)
        },
        Aggregations =
            new TermsAggregation("project_tags") { Field = Field<Project>(p => p.CuratedTags.First().Name.Suffix("keyword")) }
    }
}

Example json output. 

{
  "aggs": {
    "projects_by_state": {
      "filters": {
        "other_bucket": true,
        "filters": [
          {
            "term": {
              "state": {
                "value": "BellyUp"
              }
            }
          },
          {
            "term": {
              "state": {
                "value": "Stable"
              }
            }
          },
          {
            "term": {
              "state": {
                "value": "VeryActive"
              }
            }
          }
        ]
      },
      "aggs": {
        "project_tags": {
          "terms": {
            "field": "curatedTags.name.keyword"
          }
        }
      }
    }
  }
}

Handling Responsesedit

Using the .Agg aggregation helper we can fetch our aggregation results easily in the correct type. Be sure to read more about .Aggs vs .Aggregations

response.ShouldBeValid();

var filterAgg = response.Aggs.Filters("projects_by_state");
filterAgg.Should().NotBeNull();
var results = filterAgg.AnonymousBuckets();
results.Count.Should().Be(4);

foreach (var singleBucket in results.Take(3))
{
    singleBucket.DocCount.Should().BeGreaterThan(0);
}

results.Last().DocCount.Should().Be(0); 

The last bucket is the other bucket

Empty Filtersedit

Fluent DSL exampleedit

s => s
.Aggregations(aggs => aggs
    .Filters("empty_filters", agg => agg
        .AnonymousFilters()
    )
)

Object Initializer syntax exampleedit

new SearchRequest<Project>
{
    Aggregations = new FiltersAggregation("empty_filters")
    {
        Filters = new List<QueryContainer>()
    }
}

Example json output. 

{
  "aggs": {
    "empty_filters": {
      "filters": {
        "filters": []
      }
    }
  }
}

Handling Responsesedit

response.ShouldBeValid();
response.Aggs.Filters("empty_filters").Buckets.Should().BeEmpty();

Conditionless Filtersedit

Fluent DSL exampleedit

s => s
.Aggregations(aggs => aggs
    .Filters("conditionless_filters", agg => agg
        .AnonymousFilters(
            q => new QueryContainer()
        )
    )
)

Object Initializer syntax exampleedit

new SearchRequest<Project>
{
    Aggregations = new FiltersAggregation("conditionless_filters")
    {
        Filters = new List<QueryContainer>
        {
            new QueryContainer()
        }
    }
}

Example json output. 

{
  "aggs": {
    "conditionless_filters": {
      "filters": {
        "filters": []
      }
    }
  }
}

Handling Responsesedit

response.ShouldBeValid();
response.Aggs.Filters("conditionless_filters").Buckets.Should().BeEmpty();